In the oil and gas industry, some techniques for exploring and/or extracting hydrocarbons from the earth include operations that are to be performed by a well tool located downhole in a wellbore and that require application of a deployment or activating force only when the well tool is located at a target position downhole. Examples include, but are not limited to, actuated deployment of sensors in the wellbore, forced engagement of sensors with subterranean formations, locking or anchoring downhole the well tool in a desired downhole location, diverting fluid flow (for example by actuated movement of diverter sleeves), activating downhole power storage, and releasing downhole sensors.
For this purpose, well tools often include remotely controllable actuators incorporated in the tool and configured for actuating downhole deployment of the tool. Operator control over activation and/or deactivation of the downhole actuator at an operator-selected time and/or at a target position along the wellbore is achieved by the provision of a control channel between the downhole tool and the surface. In some cases, downhole actuators are electrically powered by electrical conductors ran downhole from the surface and/or by downhole storage devices. In some instances, the actuators are hydraulically powered by means of an electrically controlled and powered pump in a liquid-filled sealed fluid circuit (e.g., containing hydraulic oil as actuating medium). Electrical conductors may in such cases again be run downhole to the pump for powering the hydraulic circuit. Electrical conductors and electronic components of some downhole actuators can display sub-optimal performance and/or reliability in particularly harsh downhole conditions, for example at high ambient temperatures. Actuators in high temperature optical fiber applications, for example, can typically be exposed to downhole conditions in which the tool electronics can be prone to failure or non-responsiveness.